Apparatus for installing fasteners and explosive loads for use therewith

ABSTRACT

A bracket for attachment to an overhead substrate to carry a suspending wire or rod is formed from metal plate or strap stock having a bend connecting a first generally rectangular section of the stock with a second generally rectangular section of the stock. The first generally rectangular section of stock has a dimple formed on one side of the stock with a corresponding bulge protruding from the other side. The bulge protrudes alongside the second generally rectangular section of stock. The bulge has a base and an apex, a generally conical outside surface adjacent to the first generally rectangular section of stock and a through aperture at the apex. The bracket is applied with a tool that can be provided with a washer system to accommodate different fastener lengths and a safety to deactivate the triggering mechanism.

FIELD OF THE INVENTION

This invention relates broadly to explosively driven fasteners Moreparticularly, this invention relates to an apparatus for installingexplosively driven fasteners and explosive loads and brackets for usetherewith.

INCORPORATION BY REFERENCE

The disclosure of U.S. Pat. No. 8,397,969 issued Mar. 19, 2013 isincorporated by reference herein.

BACKGROUND OF THE INVENTION

The fasteners with brackets as disclosed in U.S. Pat. No. 8,397,969 areof unitary construction. However, power charges, nail lengths, andbracket configuration are all individually optimized for a givenapplication. This variability requires a large inventory of the possiblepower charge/nail/bracket combinations for steady work on a project,causing high inventory costs. Also, in the event of a misfire, bentnail, or excessively spalled penetration, nothing can be salvaged of thepower charge/nail/bracket combination, causing waste cost to beundesirably high.

OBJECTS OF THE INVENTION

It is therefore an object of the invention to provide an improved toolfor installing an explosively driven fastener that can accommodate nailsof different lengths as well as an improved explosively driven fastenerfor use therewith that permits changeout of bracket configurations andsalvage of components in the event of a malfunction.

It is a further object of this invention to provide a tool that is saferto unload or clear in the event of a malfunction or failure to fire.

SUMMARY OF THE INVENTION

One embodiment of the invention is in the form of a bracket forattachment to an overhead substrate to carry a suspending wire or rod.The bracket is formed from metal plate or strap stock having a bendconnecting a first section of the stock with a second section of thestock. The sections are preferably generally rectangular. The firstsection of stock defines an aperture, preferably at the bottom of adimple formed on one side of the stock, preferably by stamping, with acorresponding protuberance, for example, an extrusion, tube or a bulge,preferably a bulge, protruding from the other side. The bulge protrudesalongside the second section of stock. The bulge has a base and an apex,a generally conical outside surface adjacent to the first section ofstock and a through aperture at the apex.

The bracket will ride on the end of a tool that carries a nail extendingloosely through the aperture and has a nest depression to accommodatethe protuberance. The tool preferably is adjustable to accommodatedifferent length nails. The bracket is preferably provided with apre-tied wire. As compared to systems that use brackets that are pressfitted to nails, the number of inventory items is greatly reduced.

Another embodiment of the invention is provided in the form of a toolfor installing an explosively driven fastener. The fastener includes anail, an explosive load attached to the nail, and a separate bracket.The tool comprises a receiver, a firing pin plunger, a firing pinspring, a firing pin, and a muzzle assembly. The firing pin plunger islocated within the receiver. The firing pin plunger has a proximal endand a distal end. The firing spring is arranged to bias the firing pinplunger out of the receiver. The firing pin has a proximal end and adistal end. The distal end is pointed. The firing pin is separate fromthe firing pin plunger. The proximal end of the firing pin is removablycoupled to the distal end of the firing pin plunger. The assembly has aproximal end and a distal end. The proximal end is arranged to receivethe firing pin and the distal end is arranged to receive the nail andexplosive load, and a portion of the bracket, such that when thefastener is placed on the distal end of the muzzle assembly and thefiring pin plunger is biased out of the receiver by the firing spring,the firing pin strikes the explosive load causing the explosive load toexplode and drive the nail out of the muzzle assembly.

Another embodiment of the invention is provided in the form of a toolhaving a safety device for installing an explosively driven fastener,the fastener including a nail and an explosive load attached to thenail. The tool comprises a receiver, a firing pin plunger, a firingspring, a firing pin, a muzzle assembly, a trigger plunger and spring, afiring pin guide, and a safety blocking element. The firing pin plungeris located within the receiver. The firing pin plunger has a proximalend and a distal end. The firing spring is arranged to bias the firingpin plunger out of the receiver. The firing pin has a proximal end and adistal end. The distal end is pointed. The firing pin is separate fromthe firing pin plunger. The proximal end of the firing pin is removablycoupled to the distal end of the firing pin plunger. The assembly has aproximal end and a distal end. The proximal end is arranged to receivethe firing pin and the distal end is arranged to receive the nail andexplosive load, and a portion of the bracket, such that when thefastener is placed on the distal end of the muzzle assembly and thefiring pin plunger is biased out of the receiver by the firing spring,the firing pin strikes the explosive load causing the explosive load toexplode and drive the nail out of the muzzle assembly. The firing pinguide extends into the receiver, the inner sleeve and the muzzleassembly. The firing pin guide has an outer flange; and the inner sleevehas an inner flange engageable by the outer flange. The trigger plungerand trigger spring are mounted transversely in the firing pin plunger,the trigger being biased radially outward from within the firing pinplunger. The firing pin guide has a slot extending from the proximal endand a widened area in the slot to receive the trigger plunger, and thereceiver has an internal trigger shoe receivable by the keyway todepress the trigger plunger by sliding over it. When the tool is in afirst resting position, the trigger plunger rests in the widened area ofthe slot thereby limiting distal movement of the firing pin, and whenthe tool is in a second firing position, the trigger shoe depresses thetrigger plunger out of engagement with the firing pin guide allowsdistal movement of the firing pin under the action of the firing spring.The receiver has a first end a second end and a sidewall extendingbetween the first end and the second end. The receiver defines atransverse borehole extending though the sidewall. The safety blockingelement is mounted for radial movement in the borehole to selectivelyblock the firing pin guide from proximal movement. When engaged, thesafety blocking element prevents the firing pin guide from movingsufficiently proximally in the receiver for the trigger plunger to bedepressed by the shoe.

In another embodiment of the invention, a tool for installing anexplosively driven fastener comprises a receiver, a firing pin plunger,a firing spring, a firing pin, a muzzle assembly, and a rubber spallshield carrying a magnet. The fastener includes a nail, an explosiveload attached to the nail, and a separate bracket. The bracket caninclude a depending wire which can be temporarily retained on the sideof the tool or its mounting pole by a second magnet. The firing pinplunger is located within the receiver. The firing pin plunger has aproximal end and a distal end. The firing spring is arranged to bias thefiring pin plunger out of the receiver. The firing pin has a proximalend and a distal end. The distal end is pointed. The firing pin isseparate from the firing pin plunger. The proximal end of the firing pinis removably coupled to the distal end of the firing pin plunger. Themuzzle assembly has a proximal end and a distal end, the proximal end isarranged to receive the firing pin and the distal end is arranged toreceive the nail and explosive load, and a portion of the bracket, suchthat when the fastener is placed on the distal end of the muzzleassembly and the firing pin plunger is biased out of the receiver by thefiring spring, the firing pin strikes the explosive load causing theexplosive load to explode and drive the nail out of the muzzle assembly.The rubbery spall shield surrounds the distal end of the muzzle assemblyand has a distal end approximately coplanar with the distal end of themuzzle assembly. The rubbery spall shield carries a magnet formagnetically attaching to a portion of the bracket to locate the bracketuntil the firing pin strikes the explosive load.

Another embodiment of the invention is in the form of a bracket carryinga plastic bushing sized on its outside to closely fit an aperture in thebracket and on its inside to closely fit over a nail carried in a nailgun.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal cross section of a tool in a first, relaxedconfiguration according to an embodiment of the invention.

FIG. 2 is a longitudinal cross section of the tool of FIG. 1 in asecond, cocked configuration and carrying a nail and charge.

FIG. 3 is a longitudinal cross section of the tool of FIG. 2 in a third,triggered configuration.

FIG. 4 is a longitudinal cross section of the tool of FIG. 2 in afourth, firing configuration.

FIG. 5 is a longitudinal cross section of the tool of FIG. 2 in a fifth,safe configuration.

FIG. 6 is a longitudinal cross section of the tool of FIG. 2 is a sixth,unload configuration.

FIG. 7 is a perspective view of an end of a tool according to anembodiment of the invention showing placement of a nail and charge.

FIG. 8 is a perspective view of the end of the tool as in FIG. 7 afterplacement of the nail and charge.

FIG. 9 is a perspective view of the end of the tool as in FIG. 8 showingplacement of a bracket on the nail and end of the tool.

FIG. 10 is a longitudinal cross section of an end of a tool according toanother embodiment of the invention illustrating placement of a nail andcharge.

FIG. 11 shows fasteners according to embodiments of the invention.

FIG. 12 shows nail/charge combinations according to embodiments of theinvention,

FIG. 13 shows washer/spacers according to an embodiment of theinvention.

FIG. 14 shows a nail/charge/bracket combination according to anembodiment of the invention, in cross section.

FIG. 15 shows an exploded view of a tool according to an embodiment ofthe invention, in longitudinal cross section.

FIG. 16 is a perspective view of the end of the tool in one embodimentof the invention showing placement of a magnet in the spall shield ofthe tool.

FIG. 17 is a sectional view of the end of the tool as shown in FIG. 16when carrying a nail/charge/bracket in accordance with an embodiment ofthe invention.

FIG. 18 is a cross sectional view of a bushing showing certain featuresof another embodiment of the invention.

FIG. 19 is a cross sectional view of a bracket which can be used withthe bushing of FIG. 18.

FIG. 20 is a cross sectional view of a gun assembly as in earlierdescribed embodiment with which the newly described embodiment can beused.

FIG. 21 is a cross sectional view of a bushing/bracket combination readyfor insertion into the gun assembly of FIG. 20.

FIG. 22 is a cross sectional view of the bushing/bracket combination ofFIG. 21 after insertion into the gun assembly.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 11, one embodiment of the invention is in theform of a bracket, for example, one of brackets 2, 2′, 2″ for attachmentto an overhead substrate to carry a suspending wire or rod. The bracketis formed from metal plate or strap stock having a bend 4, preferably aright-angle bend, connecting a first section 6 of the stock with asecond section 8 of the stock. The sections are preferably generallyrectangular. The first generally rectangular section of stock has aperforation, for example, at the bottom of a dimple 10 formed on oneside of the stock, preferably by stamping, with a correspondingprotuberance 12 protruding from the other side, for example, anextrusion, bulge or tubing, preferably a bulge. The bulge or otherprotuberance protrudes alongside the second generally rectangularsection of stock. The bulge has a base 14 and an apex 16, a generallyconical outside surface adjacent to the first generally rectangularsection of stock and a through aperture 18 at the apex. The insidesurface of the bulge is also generally conical. In one preferredembodiment, the bracket 2 further comprises a third section 21 of stock,preferably a rectangular section, connected to the second generallyrectangular section of stock by a generally right-angle bend andextending therefrom in a plane generally parallel to the first generallyrectangular section of stock in a direction away from the bulge. Thethird section of stock defines an aperture 22. In another embodiment,the second generally section of stock of the bracket 2″ defines a secondaperture 20. In another embodiment, the second aperture 24 of thebracket 2′ is threaded to accept a threaded rod, not shown.

In a preferred embodiment, the generally conical outside surface of thebulge converges in the direction of the apex of the bulge at ahalf-angle in the range of about 30 to about 60 degrees. The bulge has aheight that is 30 to 50% of its outside diameter at the base. The stockis steel, the first rectangular section has a length in the range ofabout 1 to about 4 cm, a width in the range of about 1 to about 4 cm, athickness in the range of about 0.1 to about 0.3 cm, and the bulge hasan outside diameter at the base in the range of about 0.5 to about 1 cm.

The brackets of the invention are used in conjunction with a nail 30.See FIGS. 10 and 14. Different length nails 30′, 30″ for example can beused for different application. See FIG. 12. The nail has a cylindricalshaft 31 (See FIG. 7), a longitudinal axis, a pointed distal end 32 anda proximal nail head 34. The cylindrical shaft is positioned loosely andslidably in the through-aperture of the apex (see FIG. 14) with thepointed distal end protruding in the range of about 0.1 to about 0.5 cmabove a surface 7 of the first generally rectangular surface opposite tothe protuberance. See FIG. 9.

With reference to FIG. 7 for example, the nail is preferably used incombination with a plastic cap 35 having a distal end, a proximal end,and a longitudinal axis. The distal end surrounds the nail head. Theproximal end contains a nitrocellulose load 36. Different strength loadscan be provided if needed. The plastic cap is generally cylindrical inshape and has its longitudinal axis positioned coaxially with thelongitudinal axis of the nail shaft. The plastic cap preferably has anoutside diameter slightly smaller than the outside diameter of the bulgeor other protuberance at its base 14. The cap, nitrocellulose load, andnail are manufactured as a unit.

The nail generally has a length between the distal end and the proximalend that is in the range of 2 to 5 cm and the plastic cap and/ornitrocellulose load is preferably color-coded dependent on the length ofthe nail.

Conventional fasteners are comprised of nails and brackets hooks orclips that are mostly assembled using a press-tight fitting or throughadditional metal fittings that need to be combined before use. Thedisadvantage of this design is that when the assembled, completefastener fails to fix to the substrate or the nail fails to shoot, theentire fastener assembly is scrapped and cannot be reused, resulting inexcess waste. This invention can reuse the same bracket and, providingthat the nail/cap/load piece is replaced, reduces waste.

As compared to using a tight-fitting bracket, the bracket only looselycovers the nail piece in the invention, and the tool is adjusted with acolor-coded washer 44, 44′, 44″ for example so that the point of thenail piece protrudes above the bracket no more than 5 millimeters. Abowl-shaped structure is provided on the underside of the bracket whichenters completely into the tool beneath the bracket beneath the nailtip. This bowl structure enters completely into the tube of the toolcover, preventing nails from sliding when applying the bracket to thesubstrate. The feature assures that the nail is driven in straight.

To determine the shortest usable nail length, load the nail into thenosepiece of the tool until the head of the nail starts to touch thefiring pin guide inside of the tool, then loosely encase the nail withthe hook/clip bracket piece. When the point of the nail protrudes nomore than 5 millimeters the shortest length of nail that can be used hasbeen determined. The solution to the issue of coupling different lengthsof nails is in utilizing different thicknesses of spacers to adjust thenail protrusion. The different lengths of spacers allow differentlengths of nails to be loaded into the tube and ensure that afterequipping the bracket the nail does not protrude more than within a5-millimeter range outside the barrel of the nosepiece.

The combination is preferably used in conjunction with a muzzle assembly40, (See FIG. 10) a color coded washer 44, 44′, 44″, an inner sleeve 46,and a receiver 48 (see FIG. 1). The inner sleeve has a distal annularendface and a proximal end. The muzzle assembly defines a generallycylindrical throughbore 50 and having a distal end and a proximal endand the distal end defines an annular endface 42. The distal end of themuzzle assembly closely receives the proximal end of the plastic cap inthe throughbore. The proximal end of the muzzle assembly is threaded tothe inner sleeve. The color-coded washer is retained between annularendfaces on the muzzle assembly and the inner sleeve. The inner sleeveis slidably carried by the receiver.

The distal annular endface of the muzzle assembly contacts the firstsection of stock. See FIG. 9. A rubbery spall shield 52 is preferablycarried on the muzzle assembly and has a segment cutaway 54 toaccommodate the bracket. The cutaway has the added benefit of preventingthe bracket from spinning around during manipulation of the tool. Thespall shield has a distal annular endface that surrounds and isapproximately co-planar with the distal annular endface of the muzzleassembly. A magnet 55 is preferably mounted in a recess, for example, aborehole, in the distal annular endface of the spall shield. The magnetis preferably located between the distal annuar endface of the muzzleassembly and the cutaway. See FIG. 16. The magnet can be cylindricallyshaped and can be secured by adhesive. The magnet preferably has a flatdistal face that is approximately co-planar with the distal annularendface of the spall shield. The magnet helps locate the bracket afterit has been placed. See FIG. 17. The tool further comprises a firing pinguide 56 having a distal end and a proximal end slidably mounted in thegenerally cylindrical throughbore of the muzzle assembly. The distal endof the firing pin guide supports the proximal end of the plastic cap sothat the pointed distal end of the nail protrudes in the range of about0.1 to about 0.5 cm above a surface of the first generally rectangularsurface of the bracket opposite the protruding bulge. The color codedwasher has a thickness as measured longitudinally which is related tothe color code of the plastic cap and/or nitrocellulose load to spacethe distal end of the muzzle assembly from the distal end of the innersleeve adequately to cause the distal end of the nail to protrude abovethe surface of the bracket in the range of 0.1 to 0.5 cm when the colorsmatch.

The generally cylindrical throughbore of the muzzle assembly preferablyhas an inside diameter that is slightly larger than an outside diameterof the plastic cap. The throughbore preferably has a chamfer where itopens onto the distal endface of the muzzle assembly to provide a nestfor the bulge. By accommodating the bulge, a proximal surface of thebracket can lie flat against the distal end surface of the muzzleassembly so that the bracket is stably positioned on the end of thetool.

In a preferred embodiment, the firing pin guide has an annular outwardlyextending proximally facing flange 58 between the distal end and theproximal end and the inner sleeve has an annular inwardly extendingdistally facing flange 60 between the distal end and the proximal endfor abutting the annular outwardly extending proximally facing flange ofthe firing pin guide. See FIG. 6. This causes the firing pin guide andthe inner sleeve to move proximally together when the firing pin guideis urged proximally.

The receiver has a first end 62 a second end 64 and a sidewall extendingbetween the first end and the second end. The receiver defines atransverse borehole 66 extending though the sidewall. A safety blockingelement 68 is mounted for radial movement in the borehole to selectivelyblock the firing pin guide from proximal movement. Compare FIGS. 1 and5. The receiver further carries a trigger shoe 70 extending radiallyinwardly from the sidewall of the receiver at a location between thesafety blocking element and the proximal end of the receiver.

A firing pin 72 is mounted in the firing pin guide. A firing pin plunger74 is mounted to the firing pin and extends longitudinally proximallytherefrom. A trigger plunger 76 is mounted in a transverse passage infiring pin plunger and is biased radially outwardly to move proximallywith the firing pin guide until depressed by the trigger shoe. Thesafety blocking element when engaged prevents the firing pin guide frommoving sufficiently proximally for the trigger plunger to be depressedby the shoe.

In a preferred embodiment, an outer sleeve 78 is mounted on thereceiver. The outer sleeve has a longitudinal axis, a longitudinallyextending inner slot 80, and an outwardly protruding portion 82 defininga radially outwardly extending ridge over the slot. See FIG. 6. Theradially extending ridge defining a transverse borehole and a cam 84 ismounted in the borehole and extends across the slot. An arm 86 ismounted on one end of the cam to permit about a 90-degree rotation ofthe cam. The outer sleeve is mounted on the receiver so that the camdepresses the safety blocking element and prevents the firing pin guidefrom moving sufficiently proximally for the trigger plunger to bedepressed when actuated.

The distal end of the firing pin guide is near the distal end of thebarrel when the firing pin guide contacts the safety blocking element topermit ejection of the plastic cap from the generally cylindricalthroughbore of the muzzle assembly by moving the inner sleeveproximally. See FIG. 6. The blocking element preferably comprises a ballbearing, as illustrated.

Another embodiment of the invention is provided in the form of a tool100 for installing an explosively driven fastener. The fastener includesa nail, an explosive load attached to the nail, and a separate bracket.The tool comprises a receiver 48, a firing pin plunger 74, a firingspring 75, a firing pin 72, and a muzzle assembly 40. The firing pinplunger is located within the receiver. The firing pin plunger has aproximal end and a distal end. The firing spring is arranged to bias thefiring pin plunger out of the receiver. The firing pin has a proximalend and a distal end. The distal end is pointed. The firing pin isseparate from the firing pin plunger. The proximal end of the firing pinis removably coupled to the distal end of the firing pin plunger. Themuzzle assembly has a proximal end and a distal end. The proximal end isarranged to receive the firing pin and the distal end is arranged toreceive the nail and explosive load, and a portion of the bracket, suchthat when the fastener is placed on the distal end of the muzzleassembly and the firing pin plunger is biased out of the receiver by thefiring spring, the firing pin strikes the explosive load causing theexplosive load to explode and drive the nail 30 out of the muzzleassembly.

Preferably, the tool further comprises an inner sleeve 46 coaxiallymounted within the receiver. The inner sleeve has a proximal end and adistal end. An inner sleeve spring 47 biases the inner sleeve away fromthe receiver. An annular spacer 44 is positioned between the distal endof the annular sleeve and the proximal end of the muzzle assembly. Thefastener includes the nail 32, an explosive load 36 attached to thenail, and a separate bracket 2 loosely penetrated by the nail. Thedistal end of the muzzle assembly is chamfered to nest a portion of thebracket which is bulged out frustoconically. If desired, a secondannular spacer having a different thickness longitudinally than theannular spacer can be provided to change a distance that the distal endof the nail protrudes from the distal end of the muzzle assembly orprovide for the use of different length nails. Generally speaking, thespacer has an adequate thickness to cause the distal end of the nail toprotrude in the range of 0.1 to 0.5 cm above the distal end of themuzzle assembly. Preferably, a distal end of the muzzle assemblysupports most of a flat portion of the bracket around the bulge. Morepreferably, the distal end of the muzzle assembly supports most all of aflat portion of the bracket around the bulge. See FIG. 9.

This invention also adds a series of spacers with different thicknessesbased on the existing tool, which is used to adjust the tool to allowthe use of different lengths of pins. The invention allows the user tobe able to match all different kinds of hooks & clip devices dependingon application, greatly increasing its versatility, thus reducingproduct SKU's and lowering inventory cost.

In a preferred embodiment, the tool comprises a firing pin guide 56extending into the receiver, the inner sleeve and the muzzle assembly.The firing pin guide has an outer flange 58 and the inner sleeve has aninner flange 60 engageable by the outer flange. A trigger plunger 76 anda trigger spring 77 mounted transversely in the firing pin plunger, thetrigger being biased radially outward from within the firing pinplunger. The firing pin guide has a slot 57 extending from the proximalend and a widened area 59 in the slot to receive the trigger plunger.The receiver has an internal trigger shoe 70 receivable by the keyway todepress the trigger plunger by sliding over it. When the tool is in afirst resting position, (FIG. 1) the trigger plunger rests in thewidened area of the slot thereby limiting distal movement of the firingpin. When the tool is in a second firing position (FIG. 3), the triggershoe depresses the trigger plunger out of engagement with the firing pinguide and allows distal movement of the firing pin under the action ofthe firing spring.

In a preferred embodiment, the receiver has a first end a second end anda sidewall extending between the first end and the second end. Thereceiver defines a transverse borehole 66 extending though the sidewall.The tool further comprises a safety blocking element 68 mounted forradial movement in the borehole to selectively block the firing pinguide from proximal movement. The safety blocking element when engagedprevents the firing pin guide from moving sufficiently proximally forthe trigger plunger to be depressed by the shoe.

More preferably, an outer sleeve 78 is mounted on the receiver. Theouter sleeve has a longitudinal axis, a longitudinally extending innerslot, and an outwardly protruding portion 82 defining a radiallyoutwardly protruding, longitudinally extending ridge over the slot. Theridge defines a transverse borehole. A cam 84 is mounted in the boreholeand extends across the slot. An arm 86 on one end of the cam permitsabout a 90-degree rotation of the cam. The outer sleeve is positioned onthe receiver so that the cam depresses the safety blocking element andprevents the firing pin guide from moving sufficiently proximally forthe trigger plunger to be depressed.

Another embodiment of the invention is provided in the form of a tool100 having a safety device for installing an explosively drivenfastener, the fastener including a nail and an explosive load attachedto the nail. The tool comprises a receiver 48, a firing pin plunger 74,a firing spring 75, a firing pin 72, a muzzle assembly 40, a triggerplunger 76 and spring 77, a firing pin guide, and a safety blockingelement. The firing pin plunger is located within the receiver. Thefiring pin plunger has a proximal end and a distal end. The firingspring is arranged to bias the firing pin plunger out of the receiver.The firing pin has a proximal end and a distal end. The distal end ispointed. The firing pin is separate from the firing pin plunger. Theproximal end of the firing pin is removably coupled to the distal end ofthe firing pin plunger. The assembly has a proximal end and a distalend. The proximal end is arranged to receive the firing pin and thedistal end is arranged to receive the nail and explosive load, and aportion of the bracket, such that when the fastener is placed on thedistal end of the muzzle assembly and the firing pin plunger is biasedout of the receiver by the firing spring, the firing pin strikes theexplosive load causing the explosive load to explode and drive the nail30 out of the muzzle assembly. The firing pin guide extends into thereceiver, the inner sleeve 46 and the muzzle assembly. The firing pinguide has an outer flange 58 and the inner sleeve has an inner flange 60engageable by the outer flange. The trigger plunger 76 and triggerspring 77 are mounted transversely in the firing pin plunger, thetrigger being biased radially outward from within the firing pinplunger. The firing pin guide has a slot 57 extending from the proximalend and a widened area 59 in the slot to receive the trigger plunger,and the receiver has an internal trigger shoe 70 receivable by thekeyway to depress the trigger plunger by sliding over it. When the toolis in a first resting position, the trigger plunger rests in the widenedarea of the slot thereby limiting distal movement of the firing pin, andwhen the tool is in a second firing position, the trigger shoe depressesthe trigger plunger out of engagement with the firing pin guide allowsdistal movement of the firing pin under the action of the firing spring.

The receiver has a first end a second end and a sidewall extendingbetween the first end and the second end. The receiver defines atransverse borehole 66 extending though the sidewall. The safetyblocking element 68 is mounted for radial movement in the borehole toselectively block the firing pin guide from proximal movement. Whenengaged, the safety blocking element prevents the firing pin guide frommoving sufficiently proximally in the receiver for the trigger plungerto be depressed by the shoe.

More preferably, an outer sleeve 78 mounted on the receiver. The outersleeve has a longitudinal axis, a longitudinally extending inner slot,and an outwardly protruding portion defining a radially outwardlyprotruding, longitudinally extending ridge over the slot. The ridgedefines a transverse borehole. A cam 84 is mounted in the borehole andextends across the slot. An arm 86 on one end of the cam permit about a90-degree rotation of the cam. The outer sleeve is mounted on thereceiver so that the cam blocks radially outward movement of the safetyblocking element and prevents the firing pin guide from movingsufficiently proximally for the trigger plunger to be depressed when itis actuated. Preferably, the safety blocking element comprises a ballbearing.

One embodiment of the invention is to provide a safety device thatprevents the firing function of the tool when the safety is properlyengaged. Besides conforming to the traditional requirements of fasteningtools that require the user apply a specific amount of compression forceto actuate the tool upon contact with the substrate, this device has anadded safety catch to disable the device from firing when not in use.Actuating the safety while servicing the tool or dislodging jammedfasteners helps avoid accidents and ensure increased safety. A roundsteel bearing is installed in the receiver. The bearing islongitudinally spaced in front of the trigger. When used to applyfasteners, the bearing is able to move up and down radially withoutinfluencing actuation by trigger. The safety mechanism, when engaged,puts a pressure release on the head of the steel bearing which stops thebearing from moving up and down radially and prevents the radialmovement of the trigger plunger, thus inhibiting the mechanism's abilityto fire.

Another embodiment of the invention, with reference to FIGS. 18-22,comprises a bracket 2′ for attachment to an overhead substrate to carrya suspending wire or rod. The bracket is formed from metal plate orstrap stock having a bend 194, preferably a right-angle bend, connectinga first section 196 of the stock with a second section 198 of the stock.The sections are preferably generally rectangular. The first generallyrectangular section of stock has a perforation 197, for example, at thebottom of a dimple 1910 formed on one side of the stock, preferably bystamping, with a corresponding protuberance 1912 protruding from theother side, for example, an extrusion, bulge or tubing, preferably abulge. The bulge or other protuberance protrudes alongside the secondgenerally rectangular section of stock. The bulge has a base 1914 and anapex 1916, a generally conical outside surface adjacent to the firstgenerally rectangular section of stock and a through aperture 1918 atthe apex. The inside surface of the bulge is also generally conical, inthe illustrated embodiment, frustoconical where it opens onto the uppersurface of the bracket, and generally cylindrical at the aperture 1918.The aperture is of larger diameter than the aperture of earlierembodiments to accommodate a plastic bushing 1920 extending through thethrough-aperture. See FIG. 21. The bushing is preferably constructed ofa thermoplastic material, for example, Nylon®. The bushing has a firstend and a second end. An annular flange 1922 extends radially outwardlyat its first end. A through-passage 1924 extends from the first end tothe second end. The annular flange at the first end of the plasticaperture is received by the dimple on the upper surface of the bracket.The plastic bushing has a generally cylindrical or slightly taperedouter surface that is closely received by the through-aperture openingat the apex of the protuberance. In the illustrated embodiment, thebushing has at least one fin or barb 1926 protruding from its generallycylindrical outer surface contacting the apex of the protuberance toretain the annular flange in the dimple.

The bracket/bushing combination is used in combination with a nail 30,cap 35 and load 36, and gun muzzle assembly 40. The nail has acylindrical shaft, a longitudinal axis, a pointed distal end 32 and aproximal nail head 34. The cylindrical shaft is positioned snugly in thethrough-passage of the bushing, and this is different from theembodiments described earlier herein. The pointed distal end of the nailprotrudes in the range of about 0.1 to about 0.5 cm above a surface ofthe first section of stock opposite to the protuberance. The plastic caphas a distal end, a proximal end, and a longitudinal axis. The distalend surrounds the nail head and the proximal end contains thenitrocellulose load. The plastic cap is generally cylindrical in shapeand has a longitudinal axis positioned coaxially with the longitudinalaxis of the nail shaft. The plastic cap has an outside diameter slightlysmaller than the outside diameter of the protuberance at the base. Themuzzle assembly defines a generally cylindrical throughbore 50 and has adistal end and a proximal end. The throughbore closely receives theplastic cap. The throughbore having a chamfer where it opens onto thedistal endface of the muzzle assembly to provide a nest for the bulgeand to permit a proximal surface of the bracket to lie flat against thedistal end surface 42 of the muzzle assembly. Because the bushing fitssnugly onto the nail, the magnet on the distal face of the muzzleassembly can be eliminated if desired.

While certain preferred embodiments of the invention have been describedherein, the invention is not to be construed as being so limited, exceptto the extent that such limitations are found in the claims.

What is claimed is:
 1. A bracket for attachment to an overhead substrateto carry a suspending wire or rod, said bracket being formed from metalplate or strap stock having a bend connecting a first section of thestock with a second section of the stock, the first section of stockhaving a through-aperture and a corresponding protuberance on the otherside that protrudes alongside the second section of stock, saidprotuberance having a base and an apex, with the through-apertureopening at the apex.
 2. A bracket as in claim 1 wherein the bend is agenerally right-angle bend, the second generally section of stockdefines a second aperture, wherein the first and section sections ofstock are generally rectangular in shape, and wherein the base of theprotuberance has a generally conical outside surface adjacent to thefirst generally rectangular section of stock.
 3. A bracket as in claim 2further comprising a third generally rectangular section of stockconnected to the second generally rectangular section of stock by agenerally right-angle bend and extending therefrom in a plane generallyparallel to the first generally rectangular section of stock in adirection away from the bulge.
 4. A bracket as in claim 1 wherein thebracket has an upper surface and a lower surface, and the protuberanceis on the lower surface and forms a bulge having a generally conicaloutside surface, the upper surface of the bracket defining a dimpleforming the inside of the bulge.
 5. A bracket as in claim 1 furthercomprising, in combination a nail having a cylindrical shaft, alongitudinal axis, a pointed distal end and a proximal nail head, thecylindrical shaft positioned loosely and slidably in thethrough-aperture of the apex with the pointed distal end protruding inthe range of about 0.1 to about 0.5 cm above a surface of the firstsection of stock opposite to the protuberance.
 6. A combination as inclaim 5 further comprising a plastic cap having a distal end, a proximalend, and a longitudinal axis, the distal end surrounding the nail head,the proximal end containing a nitrocellulose load, said plastic capbeing generally cylindrical in shape and having a longitudinal axispositioned coaxially with the longitudinal axis of the nail shaft, saidplastic cap having an outside diameter slightly smaller than the outsidediameter of the protuberance at the base.
 7. A combination as in claim 6wherein the nail has a length between the distal end and the proximalend that is in the range of 2 to 5 cm and the plastic cap and/ornitrocellulose load is color-coded dependent on the length of the nail.8. A combination as in claim 7 further comprising a muzzle assemblyhaving a distal annular endface and a proximal annular endface, a colorcoded washer, an inner sleeve, and a receiver, the inner sleeve having adistal annular endface and a proximal end, the muzzle assembly defininga generally cylindrical throughbore and having a distal end and aproximal end, the distal end of the muzzle assembly closely receivingthe proximal end of the plastic cap, the proximal end of the muzzleassembly being threaded to the inner sleeve, the color coded washerbeing retained between annular endfaces on the muzzle assembly and theinner sleeve, and the inner sleeve being slidably carried by thereceiver.
 9. A combination as in claim 8 wherein the first and secondsections of stock are generally rectangularly shaped and the distalannular endface of the muzzle assembly contacts the first generallyrectangular section of stock, said combination further comprising afiring pin guide having a distal end and a proximal end, the distal endof the firing pin guide being slidably mounted in the generallycylindrical throughbore of the muzzle assembly, the distal end of thefiring pin guide supporting the proximal end of the plastic cap so thatthe pointed distal end of the nail protrudes in the range of about 0.1to about 0.5 cm above a surface of the first generally rectangularsurface of the bracket opposite the protruding bulge.
 10. A combinationas in claim 9 wherein the color coded washer has a thickness as measuredlongitudinally which is related to the color code of the plastic capand/or nitrocellulose load to space the distal end of the muzzleassembly from the distal end of the inner sleeve adequate to cause thedistal end of the nail to protrude above the surface of the bracket inthe range of 0.1 to 0.5 cm when the colors match.
 11. A combination asin claim 9 wherein the generally cylindrical throughbore of the muzzleassembly has an inside diameter that is slightly larger than an outsidediameter of the plastic cap, and the throughbore has a chamfer where itopens onto the distal endface of the muzzle assembly to provide a nestfor the bulge and to permit a proximal surface of the bracket to lieflat against the distal end surface of the muzzle assembly.
 12. Acombination as in claim 9 wherein the firing pin guide has an annularoutwardly extending proximally facing flange between the distal end andthe proximal end and the inner sleeve has an annular inwardly extendingdistally facing flange between the distal end and the proximal end forabuting the annular outwardly extending proximally facing flange of thefiring pin guide and causing the firing pin guide and the inner sleeveto move proximally together when the firing pin guide is urgedproximally.
 13. A combination as in claim 9 wherein the receiver has afirst end a second end and a sidewall extending between the first endand the second end, said receiver defining a transverse boreholeextending though the sidewall, said combination further comprising asafety blocking element mounted for radial movement in the borehole toselectively block the firing pin guide from proximal movement.
 14. Acombination as in claim 13 wherein the receiver further carries atrigger shoe extending radially inwardly from the sidewall of thereceiver at a location between the safety blocking element and theproximal end of the receiver.
 15. A combination as in claim 14 furthercomprising a firing pin mounted in the firing pin guide, a firing pinplunger mounted to the firing pin and extending longitudinallyproximally therefrom, and a trigger plunger mounted in a transversepassage in firing pin plunger and biased radially outwardly to moveproximally with the firing pin guide until depressed by the triggershoe, wherein the safety blocking element when engaged prevents thefiring pin guide from moving sufficiently proximally for the triggerplunger to be depressed by the shoe.
 16. A combination as in claim 15further comprising an outer sleeve mounted on the receiver, said outersleeve having a longitudinal axis, a longitudinally extending innerslot, and an outwardly protruding portion defining a radially outwardlyextending ridge over the slot, said radially extending ridge defining atransverse borehole, a cam mounted in the borehole and extending acrossthe slot, and an arm on one end of the cam to permit about a 90 degreerotation of the cam, said outer sleeve mounted on the receiver so thatthe cam depresses the safety blocking element and prevents the firingpin guide from moving sufficiently proximally for the trigger plunger tobe depressed.
 17. A combination as in claim 16 wherein the distal end ofthe firing pin guide is near the distal end of the barrel when thefiring pin guide contacts the safety blocking element to permit ejectionof the plastic cap from the generally cylindrical throughbore of themuzzle assembly by moving inner sleeve proximally, wherein the blockingelement comprising a ball bearing.
 18. A bracket as in claim 4 furthercomprising, in combination, a plastic bushing extending through thethrough-aperture, said plastic bushing having a first end and a secondend, an annular flange extending radially outwardly at its first end,and a through-passage extending from the first end to the second end,the annular flange at the first end of the plastic aperture beingreceived by the dimple on the upper surface of the bracket, said plasticbushing having a generally cylindrical outer surface that is closelyreceived by the through-aperture opening at the apex of theprotuberance.
 19. A combination as in claim 18 wherein the bushing hasat least one fin or barb protruding from its generally cylindrical outersurface contacting the apex of the protuberance to retain the annularflange in the dimple.
 20. A combination as in claim 18, furthercomprising, in combination, a nail having a cylindrical shaft, alongitudinal axis, a pointed distal end and a proximal nail head, thecylindrical shaft positioned snugly in the through-passage of thebushing, with the pointed distal end protruding in the range of about0.1 to about 0.5 cm above a surface of the first section of stockopposite to the protuberance, a plastic cap having a distal end, aproximal end, and a longitudinal axis, the distal end surrounding thenail head, the proximal end containing a nitrocellulose load, saidplastic cap being generally cylindrical in shape and having alongitudinal axis positioned coaxially with the longitudinal axis of thenail shaft, said plastic cap having an outside diameter slightly smallerthan the outside diameter of the protuberance at the base, and a muzzleassembly defining a generally cylindrical throughbore and having adistal end and a proximal end, the throughbore closely receiving theplastic cap and having a chamfer where it opens onto the distal endfaceof the muzzle assembly to provide a nest for the bulge and to permit aproximal surface of the bracket to lie flat against the distal endsurface of the muzzle assembly.